Nate Anderson, 15, was home on a Wednesday evening in September with his 19-year-old sister -- parents were at work -- and decided to go for a quick jog around the family's quiet neighborhood in New Chapel Hill, about ten miles east of Tyler.

He returned to find his sister, Amanda, dead in her bedroom, shot four times in the head.

The murder shocked the small town. Amanda was a student at Tyler Junior College, working at a local hospital, and the entire family was active at Tyler Gospel Chapel, a Christian church and school.

Thinking about Nate finding his sister's body was horrifying. He didn't "know anything but the church, school and love," the boy's grandmother told news reporters.

And the family and neighbors were terrified that a cold-blooded killer could still be roaming the streets. People thought it was "gang related" and that the Smith County Sheriff's Office, the agency investigating the murder, had let the case go cold.

But then, on Novemeber 11, the bombshell: sheriff's deputies detained Nate, while he was at Tyler Gospel, for murdering Amanda. The brother was charged this week with "delinquent conduct" and is still in custody at Smith County Juvenile Detention Center.

The arrest affidavit is damning. Investigators linked the type of weapon and ammunition used to kill Amanda to a .22-caliber pistol -- in the house the night Amanda was killed -- that Nate frequently used when he and his father "would target shoot together."

Furthermore, forensic testing found microscopic blood splatter -- Amanda's blood -- on Nate's shirt, pants and shoes. "The pattern of blood on Nate Anderson's clothing," the affidavit says, "is consistent with what [the investigator] would expect to find on the shooter's clothing."

But, the parents are standing by Nate and believe he isn't responsible for the murder.

In a report on East Texas's KLTV, Mark Anderson, the father, says that sheriff's deputies are ignoring evidence in the case. There's a witness, Mark says, who saw a car pull up to the Anderson's home at the time of the murder, but investigators never questioned that witness.

"Someone else may be murdered in this town, in this community," he told KLTV. "We've had faith that [investigators] were doing the right thing, but here we are. [Nate} was there serving people in the church when they came and put handcuffs on him."

It's certainly a bizarre case, especially considering the sheriff doesn't have a motive in the killing. We weren't able to get in contact with anyone from Smith County yesterday, but we'll update when we hear anything new.